[2.1 Docs] SDK: Python and Java SDK changes #703

Documentation work verified against the merged source PRs and the 2.1.0-rc1 release for the 2.1 release. Items were checked against the code change (not only the PR title) and against the pages that exist today.

Area: Platform
Scope: OpenMetadata
Related: #527, #572

Summary
The Python and Java SDKs gained bulk create with an onConflict option, and the Python ingestion client now supports DataProduct and Page entities with a new SearchCursorStalledError. Confirm both against the SDK diff before writing; this issue is intentionally small.

Source PRs

• OpenMetadata#35910: Fixes 35909: report bulk-create outcomes and recover conflicts OpenMetadata#35910
• OpenMetadata#36013: Fixes #36012: Page data products and knowledge articles in the ingestion client OpenMetadata#36013

Doc tasks

• Document SDK bulk create with onConflict in the Python and Java SDK pages (OM#35910)
• Verify and document ingestion client support for DataProduct and Page, and SearchCursorStalledError (OM#36013)

Pages to check: sdk/ Python and Java pages

OpenMetadata-side items only. Collate-only changes are tracked in docs-collate. Page names are the docs-collate ones; locate the matching page under v2.1.x-SNAPSHOT/.